Let-back mechanism for looms



May 14, 1929. J, c. HARMON 1,712,731

LET-BACK MECHANISM FOR LOOMS Filed Sept. 4, 1928 2 Sheets-Sheet l M 1 F1 g. 1.

lnvenTor. LJuHon C. Harmon ATTys.

y 4, 1929. J. c. HARMON LET-BACK MECHANISM FOR LOOMS Filed Sept. 4, 1928 2 Sheets-Sheet 2 InvenTor \Julicm C.

Harmon M My! Anya Patented May 14, 1929.

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UNITED STATES PATENT QFFICE.

JULIAN C. HARMON, 0F KANNAPOLIS, NORTH CAROLINA, AESSIGNOR TODRAPER COR- PORATION, OF HOPIEIDALE, MASSACHUSETTS, A CORPORATION OF MAINE.

LET-BACK MECHANISM FOR LOOMS.

This invention relates to let-back mecha nism for looms. a

Looms of the class provided with mechanism for automatically replenishing the filling upon the breakage thereof or upon com plete or partial exhaustion thereof are usua ly provided with mechanism Which acts to let backthe cloth roll take up mechanism when replenishment takes place in order to prevent thin places in the cloth. So also looms of the type employed for weaving special fabrics, such as those in which a massed or corded effect of the filling is produced, or such as those in which terry fabric is produced for example, are also providedwith mechanism to let back the cloth roll tal e-up mechanism at predetermined times as required by the particular fabric being woven. 1n the latter case the let-back mechanism is usually under the control of a dobby, jacquard, or other pattern mechanism.

The operation of disconnecting the means for driving the cloth take up roll in order to secure the desired let-back requires a sub stantial force and this force has to be exerted by the detecting mechanism, the dobby, the

jacquard, or any other such mechanism as maybe employed for effecting the let-back. But this places an undesirable and often injurious strain upon these more or less deli cate mechanisms.

The object of the present invention is to provide fortheoperation of the disconnect ing means which effects let-back by some rugged. andcfpowerful constantly operating element of the loom, such for example as the lay, and to effect the operative engagement of such. element .with the disconnecting means by the relatively weak means, such as the dobby, jacquard, a detecting mechanism or other similar mechanism heretofore acting directly to operate the disconnecting means.

The nature and object of the invention will appear more fully from the accompanying description and drawings and will be par-.

ticularly pointed out in the claims. a

The invention is applicable to a wide variety of looms adapted for weaving various classes of materials wherever it is desired automatically to effect letback of the cloth. But as the broad principle of the in vention is the same under all circumstances it will be sufficient here to illustrate a portion of a loom such as would be employed in weaving a terry fabric under the control of a dobby mechanism and wherein this dobby mechanism, which stands as a type of pattern con trol mechanism is disclosed as the means for controlling the let-back operation. So also the mechanism for taking up the woven fabric with the means for driving it and the means for disconnectingthe driving means from the take-up mechanism to effect the re quired let-back may all be of any suitable type and is herein shown as of a generally familiar type such as illustrated for example in the patent to La Chapelle No. 1,647,234L, granted November lst 1927.

In the drawings, Fig. 1 is a fragmentary view chiefly in side elevation of a portion of a loom with one preferred form of the invention embodied therein; a

Fig. 2 is a front elevation of such a loom also in fragmentary form.

As the general construction and operation of. a loom such as that illustrated is well known and familiar to those skilled in the art it will only be necessary to describe in detail those parts immediately concerned with the preferred embodiment of the invention illustrated.

One of the side frames 1 of the loom is shown with the usual. connecting breast beam 2' and the various shafts and other elements common to such looms. The lay comprising the lay proper 2 and the swords 3 is mounted to roclron the usual lay rock shaft l and is given its usual regular constant vibration in the usual manner. The lay, as will be recognized by those skilled in the art, a heavy powerful device and exerts a very powerful force in its rocking movement.

The cloth as it is woven passes forward over the lay beneath the breast beam 52 and is taken up by the usual take-up roll 5 and then wound up upon the usual cloth rolh not shown. The take'up roll 5 is provided with roughened surface to grip and hold the cloth. This take-up roll has its shaft 6 j om nalled inthe loom side frames and is positively and continuously driven to effect the taking up of. the cloth. One of the usual mechanisms for thus positively driving the take-up roll is illustrated as con'iprising a driven shaft 7 having a worm and worm wheel connection 8 to a shaft 9 carrying a pinion 10. This pinion is connected by a train of gearing ll. to the shaft 6. The pinion 10 is usually integral, with the ratchet Wheel i 12 to control the amount of let-back and these 1 elements are loose on the shaft 9. A suitable clutch is mounted on the shaft 9 and is shown as-comprising a toothed element 13 integral with the pinion 10 and .a toothed element fOllllGCl on a sleeve 11 keyed to and mounted to slide on the shaft 5) and nornmlly pressed by a powerful spring 15 into engagement with the element 13. I twill thus be seen that under normal cond tions the cloth take-up roll5v is positively driven through the mechanism described.

exertion of a very substantial force to overcome the spring 15.

In orderto effect the disconnecting moveinent of the clutch element 14 a usual type of hell crank lever is shown fulcrumed at 16 on the loom frame and having one arm 17 yoke-shaped and provided with studs 18 en- I gaging the shouldered face ofthe clutch element 14 while the other arm 19 extends backwardly from the fulcrum. Thusby pulling down on the arm 19 the disconnecting operation will be effected. I Y

In the construction illustrateda second bell crank lever is fulcrumcd at 20 on the loom frame and has one arm 21 extending for- I wardly and connected by a link 22 to the arm' 19 of the first bell crank lever while the other arm 23 extends downward. If then the arm 23 be pulled'rearwardly it will be seen that thefclutch will be disconnected.

A latch element is shown extending transversely of the lay connected at one end to the arm 23 of the second bell crank lever andadapted to be engaged with the sword 3 of the lay. Thislatch is shown as coniprising two parts 24 and25 a'djustably eonnected together by the set screw and slot con-- nection 26. The part 25 is pivoted at its forward end to the arm 23 of the second bell crank lever. The part 24 is provided with a hook-shaped recess 27 adapted to engage with a stud 28 carried bya bracket 29 bolted to the lay sword 3; If now this latch be raised so that its hooked recess 27 is caught by the stud 28 on thepowerful rocking lay the latch 'willb e pulled rearward and, through the mechanismdescribed, will effect the disconnection of the clutch. But it will be seen that a relatively weak force is all that is required to raise the latch24 into engagement with the lay and that when it is so raised into engagement with the'lay this latch will be pulled by the relatively powerful force exerted by the lay to effect the disconnecting operation and thus the required let-back. The latch, therefore, may be operated by any of the usual relatively delicate mechanisms which it is desired should control the let-hack, such for example as the dobby, jacquard, detecting mechanism or other similar mechanism.

As an illustration of such a mechanism a portion of a (lobby mechanism, indicated gen orally at 30, is mounted on the loom arch 31 and shown as comprising a lifter lever 32 pivoted at 33 and raised at the required times by risers 31 on a pattern chain 35. A flexible connector shown as a wire 36 extends from the free end of the lifter lever to the end of a lever 37 fulcrumed at 38 on the loom frame and a second portion of the flexible connector shown as a wire 39 extends from this lever 37 around idler directing ulleys 40 to the free end of the latch 24. referably also the flexible connector includes a helical spring 41 which acts as a givcway thus allowing the lifter lever 32 or other element to have a greater movement than necessary to raise the latch 24 into operative engagement with the stud 28.

It will thus be seen, in the illustrated cmbodimcnt of the invention, that the pattern mechanism which exerts a relatively weak force will not be strained or injured and is amply suilicient to raise the latch 24 into operative engagement with the lay when letback is required and that when this has been done the relatively powerful force exerted by the lay will effect the disconnection of the clutch and thus the required let-back.

The construction illustrated is but typical of the broad principle involved. While the latch 24, 25 operates by a pulling movement and is operated by the powerful lay when the recess 27 snaps over the stud 28 and while the latch thus has a movement in one direction, that is a rearward direction, to disconnect the clutch, and a movement in another direction, that is an upward direction, to engage the latch, various other devices may be employed in connection with other powerful constantly movable elements of the loom in order to effect the desired result in accordance with the broad principle set forth in the claims.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is

1. A loom comprisin a cloth take-up roll, means including a clutch for driving the takeup roll, clutch-disconnecting means, a relatively powerful constantly moving element, and a relatively weak means 0 erative when let-back is required to place t e clutch-disconnecting means in operative engagement with the constantly moving element therethrough to effect the disconnection of the clutch.

2. A loom comprising a cloth take-up roll, means for driving the take-up roll, means for disconnecting said driving means from the take-up roll, a relatively powerful constantly moving element, and a relatively weak means operative when let-back is required to place the said disconnecting means in operative engagement with the constantly moving element thercthrough to eli'ect the discon necting operation.

8. A loom comprising a lay and means for rocking it, a cloth take-up roll, means including a clutch for driving the take-up roll, an element inovahle in one direction to disconnect the clutch and movable in another direction to engage the lay, and means for moving the said element into engagement with the lay when let-back is required to cause the lay to move the said element in the direction required to disconnect the clutch.

4. A loom comprising a lay and means for rocking it, a cloth take-up roll, means including a clutch for driving the take-up roll, a latch and connections therefrom to the clutch acting when pulled to disconnect the clutch and thus permit let-back, and means acting when let-back is required to couple the latch to the lay and thus cause the powerful lay to pull the latch and thereby disconnect the clutch.

5. A loom comprising a lay and means for rocking it, a cloth take-up roll, means including a clutch for driving the take-up roll, a

latch and connections therefrom to the clutch acting when pulled to disconnect the clutch and thus permit let-back, and pattern-controlled means acting when let-back is required to couple the latch to the layand thus cause the powerful lay to pull the latch and thereby disconnect the clutch.

6. A looin comprising a lay and means for rocking it, a cloth take'up roll, means including a clutch for driving the take-up roll, a clutch-disconnecting lover, a latch extending transversely of the lay and connected to said lever, a connector extending to said latch, and means for moving the connector to engage the latch with the lay when let-back is required and thus cause the powerful lay to be coupled to and operate the clutell-disconnecting lever.

7. A loom comprising a lay and means for rocking it, a cloth take-up roll, means includ ing a clutch for driving the take-up roll, a clutch-disconnecting lever, a latch extending transversely of the lay and connected to said lever, a pattern-controlled lifter, a flexible connector extending from said lifter to said latch operating when the litter is raised to efi'ect the engagement of the latch with the lay and thus cause the powerful lay to be coupled to and operate the clutch-disconnecting lever.

In testimony whereof, I have signed my name to this specification.

JULIAN C. HARMON. 

